The invention concerns a measuring gauge for measuring and displaying a physical value such as pressure, for example, and more precisely a measuring gauge with at least one drag pointer element that can be coupled to the axis of rotation of a pointer, said drag pointer element being able to bi-stably accommodate 2 states, for example.
Analog rotary displays are known in connection with numerous measuring gauges. These are comprised of simple, decelerated pointers that can be carried along by the main indicator pointer in one direction per stroke and actuator.
This is interesting, for example, for reliably displaying the exceedance of the admissible pressure of a container or an hydraulic pump since this can occur briefly during the absence of the operator or the trained personnel and can go unnoticed. However, such a situation can pose a risk for the continued safe operation of the equipment.
When such a limit is exceeded and the exceedance is displayed, it may be practical or necessary to make it impossible for a single person to simply reset the display. Once the pressure is exceeded, often the safety features of the equipment must be checked or replaced, seals must be repaired or material that escaped must be disposed of safely.
To this end it is advantageous when the exceedance of a maximum limit is displayed clearly and in a mechanically irreversible manner or a reset or shut down or depressurization of the equipment is forced.
However, customary drag pointers are not suitable for this purpose. They can be manipulated or they are not resistant to vibrations. If the exceedance of an admissible value is to be displayed permanently and irreversibly to warn persons or operators of potential dangers, a display is required that reliably records the exceedance of a critical limit.
It is desirable to provide a measuring gauge that irreversibly displays an exceedance of a set or admissible threshold or maximum value in a simple manner.
According to an aspect of the invention a measuring gauge that is used for measuring and analyzing a physical value, comprises a measuring element for capturing the physical value with said measuring element, for example a Bourdon tube or such, moving according to the change of a physical value, i.e. converting a change in the physical value into a motion that can be captured. Furthermore, the measuring gauge comprises a movement that turns a pointer in a pointer plane around an axis of rotation of a pointer in relation to the motion of the measuring element, with the pointer having an actuator.
A drag pointer is spring-loaded and mounted in a pivoting manner in a bushing and can latch into a second recess when moved by the pointer.
To this end the second recess is below the first and thus ensures that the actuator of the main pointer can slide over this position of the second recess without actuating the drag pointer again or being able to move it from the final position.
The measuring gauge according to an aspect of the invention furthermore comprises preferably a dial on which the pointer indicates the physical value based on a measuring value. The drag pointer preferably is fastened below the pointer axis in order to display the exceedance of maximum values. However, it can also be fastened to different locations or to the outside circumference of the dial.
The invention is explained in more detail below based on an exemplary embodiment and reference to the drawings.